Conventionally, in order to be suppressed in power consumption, a multi-function printer is equipped with a function of switching the multi-function printer not in use to a power-saving mode. However, the operator has to wait before the multi-function printer is completely preheated after recovering from the power-saving mode.
Thus, a function of carrying a camera on a multi-function printer to detect the approach of an operator at long distance and release a power-saving mode is well known. With this function, a pre-heating operation is ended or a wait time is shortened when the operator reaches a preset position.
However, to analyze the image data of the camera to detect the approach of an operator, a Central Processing Unit (CPU) at a high speed or a high-capacity memory is needed which consumes power while acting, resulting in a problem of poor power saving effect.